Sage 'My Notebooks' menu item on Kobo Home screen

Spontaneously, from time to time, over and over again I see 'My Notebooks' menu item on Kobo Home screen

Again I connect my Kobo Sage to PC, open '.kobo/Kobo/Kobo eReader.conf', of course see that 'StylusUsageDetected' is again 'true' and change it to 'false'.

Save '.kobo/Kobo/Kobo eReader.conf' and safely remove Kobo device from PC.

'My Notebooks' menu item on Kobo Home screen disappears.

No one knows for how long this time...

What's the reason? - I am very careful not to touch 'More / My Notebooks' menu item, since I don't want to provoke my Kobo by myself. - I neither have nor use Kobo stylus.